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21.E: Diverstity of Animals (Exercises) - Biology

21.E: Diverstity of Animals (Exercises) - Biology


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21.E: Diverstity of Animals (Exercises)

Animal Diversity

To motivate and guide student observation of animal and plant similarities, diversity, and appropriateness to live in different environments to show that stories sometimes give plants and animals attributes that they don’t really have.

Context

This lesson exposes children to a wide range of animals and guides them through observation of animal similarities, differences, and environmental adaptations. This lesson can be used as part of a study of plants and animals. Before doing the lesson, students should know the meanings of the terms plant, animal, and living.

As Benchmarks for Science Literacy points out, &ldquoObserving is not enough. The students should have reasons for their observations&mdashreasons that prompt them to do something with the information they collect.&rdquo Students should be encouraged to ask questions, to find answers by careful observation, and to compare their findings with those of other students. They can use their findings to create exhibits with photos, drawings, and even live specimens from the area where they live. (Benchmarks for Science Literacy, p. 102.)

Research shows that lower elementary students tend to consider only vertebrates as animals, or to group animals by similarities in external appearance, behavior, or habitat. Young students also define plant in a narrow way, failing to classify grass, trees, and vegetables as plants. In addition, these students "typically use criteria such as &lsquomovement,&rsquo &lsquobreath,&rsquo &lsquoreproduction,&rsquo and &lsquodeath&rsquo to decide whether things are alive. Thus, some believe fire, clouds, and the sun are alive, but others think plants and certain animals are nonliving.&rdquo (Benchmarks for Science Literacy, pp. 340&ndash341.) In their study of plants and animals, students should be guided to an understanding that internal structures and processes can be more significant than external features in classification.

Because this lesson includes only online observations, students also will need ongoing opportunities for hands-on observation (using hand lenses, if appropriate) with many kinds of living plants and animals in as many environments as possible. Also, because the main lesson concentrates only on animals, students will need similar lessons that deal with plants.

Motivation

To introduce the lesson, present a living animal or plant as a hands-on classroom example. Ask students to talk about or draw things that they observe and share their observations with the class.

  • What do you see, hear, smell, or feel as you observe this plant/or animal?
  • How can plants/or animals be like each other?
  • How can they be different from each other?

Explain to students that they're about to see an online book with pictures of many animals. Their job is to observe things about these animals and to figure out how they are alike and different from each other. Another thing they will study is where these animals live and why they can live there successfully.

Development

Using the Animal Diversity student esheet, present the Where Can Animals Live? online book to the class. Pause as each graphic is displayed and ask students the questions shown with the pictures one at a time. Encourage independent questions and discussion.

Stimulate students' thinking about the animals they're observing and why they live in certain places by asking questions such as:

  • Where does this [animal] live?
  • Do you think it could live in [somewhere different]? Why or why not?
  • Do you think [something else] also could live in this [animal's] environment? Why or why not?

As the class goes through the online book, students' answers will vary. Encourage them to focus on true similarities of the animals in relation to their environments. See the Where Can Animals Live? teacher sheet for sample student responses.

Assessment

Ask a series of questions to tie together student observations during the lesson.

  • What are some ways in which all of these animals are alike?
  • How are they different?
  • What are some features that help animals live in cold environments? In hot environments? In forests or in the water?

To illustrate the main concepts of the lesson, read the book titled The Adventures of Marco and Polo by Dieter Wiesmuller. This story explores the life of a monkey (Marco) and penguin (Polo) that become friends. They visit each other's homes and decide that they'd like to live together. However, when they try to do that, they realize that they each have their own needs and need to live in their own environments.

Use this story (or another one like it) to illustrate ideas in the related benchmark for this lesson: "Stories sometimes give plants and animals attributes they really do not have."

Extensions

Use the Animal Gallery of the Smithsonian National Zoological Park to extend student learning about animal attributes, similarities, differences, and environments. Choose the option View Slide Show and page through the photos. Since there are more than 30 photos in the slide show, you may want to limit the number of pictures viewed, depending upon the capabilities of the class. Ask questions about each animal and encourage students to offer their own questions and observations.

Encourage students to choose a favorite animal from this lesson and then to carry out further research about it, using the sites listed above as well as books, videos, and web-cams. The Wildlife Facts section of the National Parks Conservation Association website can be used by older students to gather information about more than 25 wild animals. Students can report about their animals to the class.

Related Resources

CBSE Class 9 Science Notes Chapter 7 Diversity in Living Organisms

Facts that Matter

Diversity: This earth is full of organisms of various shapes and sizes. The largest Phylum of animal kingdom alone contains over a million species. There are varieties of plants, right from small grasses to tall Eucalyptus trees. This variety in living beings is called diversity.

Biodiversity: The variety of animals and plants living in a given geographical area is called biodiversity of that geographical area.
Need for a System of Classification: Because of the huge diversity in living beings it becomes very difficult task to study each of them one by one. To make their study easier animals and plants were categorized in groups and sub¬groups. Thus the system of classification started.

Classification by Aristotle: Aristotle classified animals according to their living environment. So he categorized them as either aquatic or terrestrial.

Drawbacks of Aristotle’s Classification: Both in sea as well as on land we can find animals and plants. Moreover, there are very small animals, like sea-horse, along with large animals, like whale. So, this was not a good basis of classification.

Basis of Classification
(a) Presence or Absence of Nucleus in Cells
Prokaryotes: Those organisms which have cells without well defined nucleus are called prokaryotes.
Eukaryotes: Those organisms which have cells with well defined nucleus are Called eukaryotes. Presence of nucleus and membrane-bound organelles gives better efficiency to cells.

(b) Number of Cells in an Organism
Unicellular: Those organisms having single cell are termed as unicellular organisms. In them the single cell is responsible for carrying out all necessary functions to maintain life.
Multicellular: Those organisms having more than one cell are called multicellular organisms. Because of more number of cells there can be some division of labour to gain more efficiency.

(c) Mode of Nutrition
Autotrophs: Organisms producing their own food are called autotrophs. All green plants are autotrophs. They have a pigment (chlorophyll) in green parts which facilitates photosynthesis.
Heterotrophs: Organisms dependent on either plants or animals are called heterotrophs.They don’t have chlorophylls. All animals, fungi and certain bacteria and protozoa belong to this group.

(d) Level of Organisation in Body
In multicellular organisms which are small, like hydra particular group of cells are assigned a particular function. But in larger organisms, tissues group to form an organ, which in turn make organ system. For example, in human beings there are separate systems for performing specific tasks.

Even in larger plants there is separate root system for conduction of water and minerals, leaf for photosynthesis and flowers for reproduction. Based on these characters organisms can be further classified into various sub-groups.

Evolutionary Relationship or Phylogenetic Relationship
Charles Darwin wrote a book “Origin of Species’ in 1859 and gave his theories of evolution. As per his theories all organisms have evolved from unicellular organisms. Primitive body designs came early in evolutionary history leading to more complex designs. This gave rise to such a huge diversity in life forms. Because of common ancestry, all organisms are related. The closer evolutionary relation between two organisms is also one of the basis of classification of organisms.

The Hierarchy of Classification—Groups
Biologists, such as Ernst Haeckel (1894), Robert Whittaker (1959) and Carl Woese (1977) have tried to classify all living organisms into broad categories, called kingdoms.

  • Whittaker’s Five Kingdom Classification:
    • Monera
    • Protista
    • Fungi
    • Plantae
    • Animalia.
    • Phylum (for animals)/Division (for plants)
    • Class
    • Order
    • Family
    • Genus
    • Species

    Thus, by separating organisms on the basis of a hierarchy of characteristics into smaller and smaller groups, we arrive at the basic unit of classification, which is a ‘species’. Broadly, a species includes all organisms that are similar enough to breed and perpetuate.

    • Monera
      • These organisms do not have a defined nucleus or organelles and are unicellular.
      • Cell walls present in some organisms of this group.
      • Nutrition: Autotrophic or heterotrophic
      • Examples: Bacteria and blue-green algae
      • Unicellular eukaryotic organisms.
      • Locomotion: By Jair-like cilia or whip-like flagella for moving around in some members.
      • Nutrition: Autotrophic or heterotrophic.
      • Examples: Algae, protozoans
      • Heterotrophic eukaryotic organisms.
      • Nutrition: Saprophytic they use decaying organic materials as food.
      • Multicellular eukaryotes with cell walls.
      • Nutrition: Autotrophs use chlorophyll for photosynthesis.
      • Multicellular eukaryotes without cell walls.
      • Nutrition Heterotrophs.

      Classification of Kingdom Plantae

      Thallophyta or Algae: Plants that do not have well-differentiated body design fall in this group. The plants in this group are commonly called algae. These plants are predominantly aquatic. Examples are Spirogyra, Ulothrix, Cladophora and Chora.

      Bryophyta: These are called the amphibians of the plant kingdom. The plant body is commonly differentiated to form stem and leaf-like structures. However, there is no specialized tissue for the conduction of water and other substances from one part of the plant body to another. Examples are moss (Funaria) and Marchantia.

      Pteridophyta: The plant body is differentiated into roots, stem and leaves and has specialized tissue for the conduction of water and other substances from one part of the plant body to another. Some examples are MarsUea, ferns and horse-tails.

      Gymnosperms: The plants of this group bear naked seeds and are usually perennial, evergreen and woody. Examples are pines and deodar.

      Angiosperms: This word is made from two Greek words: angio means covered and sperma—means seed. The seeds develop inside an organ which is modified to become a fruit. These are also called flowering plants. Plant embryos in seeds have structures called cotyledons.

      Cotyledons: Cotyledons are called ‘seed leaves’ because in many instances they emerge and become green when the seed germinates.
      The angiosperms are divided into two groups on the basis of the number of cotyledons present in the seed.

      • Monocotyledonous: Seeds have a single cotyledon.
      • Dicotyledonous: Seeds have two cotyledons.

      Classification of Kingdom Animalia: Kingdom Animalia is further classified into several following phylum. Each phylum has it own classes, sub-classes orders, families, etc.

      1. Porifera
        • These are non-motile animals attached to some solid support which comprises of spicules of calcium carbonate, silica.
        • There are holes or “pores’, all over the body. These lead to a canal system that helps in circulating water throughout the body to bring in food and oxygen.
        • Animals are covered with a hard outside layer or skeleton which comprises of spicules of calcium carbonate, silica.
        • They have very minimal differentiation and division into tissues.
        • Examples: Sponges
      2. Coelenterata
        • Aquatic animals.
        • There is a cavity in the body hence the name Coelenterate (coelom means cavity).
        • Body is made of two layers of cells.
        • Examples: Hydra, Jellyfish
      3. Platyhelminthes
        • The body is bilaterally symmetrical, meaning that the left and the right halves of the body have the same design.
        • There are three layers of cells from which differentiated tissues can be made, which is why such animals are called triploblastic.
        • There is no true internal body cavity or coelom, in which well developed
          organs can be accommodated.
        • The body is flattened dorsiventrally, meaning from top to bottom, which is why these animals are called flatworms.
        • They are either free-living or parasitic.
        • Examples: Planaria, Liver fluke
      4. Nematoda
        • Body is bilaterally symmetrical and triploblastic.
        • Body is cylindrical rather than flattened.
        • False body cavity or a pseudocoelom, is present.
        • These are very familiar as parasitic worms causing diseases, such as the worms causing elephantiasis (filarial worms) or the worms in the intestines (roundworm or pinworms).
        • Examples: Ascaris, Wucheraria
      5. Annelida
        • These are bilaterally symmetrical and triploblastic.
        • True body cavity present.
        • Body is divided into many ring like segments, hence the name annelida.
        • Examples: Earthworms, Leech
      6. Arthropoda
        • The largest group of animals.
        • These are bilaterally symmetrical and segmented.
        • There is an open circulatory system, and so the blood does not flow in well defined blood vessels.
        • They have jointed legs (the word ‘arthropod’ means jointed legs’).
        • Examples: Ants, Cockroach, Grasshopper, Scorpions
      7. Mollusca
        • These are bilaterally symmetrical.
        • Reduced coelomic cavity.
        • The soft body is covered with a hard shell made of calcium carbonate.
        • Examples: Snails, Mussels.
      8. Echinodermata
        • In Greek, echino means hedgehog, and derma means skin. Thus, these are spiny skinned organisms.
        • Exclusively free-living marine animals.
        • Triploblastic animals with coelom.
        • They have a peculiar water-driven tube system that they use for moving around.
        • Skeleton made of calcium carbonate.
        • Examples: Starfish and Sea urchins
      9. Protochordata
        • These animals are bilaterally symmetrical, triploblastic and have a coelom.
        • In addition, they show a new feature of body design, namely a notochord, at least at some stages during their lives.
        • The notochord is a long rod-like support structure (chord*string) that runs along the back of the animal separating the nervous tissue from the gut. It provides a place for muscles to attach for ease of movement.
        • Examples: Balanoglossus, Herdemarda and Amphioxus.
      10. Vertebrata
        These animals have a true vertebral column and internal skeleton, allowing a completely different distribution of muscle attachment points to be used for movement. Vertebrates are bilaterally symmetrical, triploblastic, coelomic and segmented, with complex differentiation of body tissues and organs. All chordates possess the following features:

      • Notochord
      • Dorsal nerve cord
      • Triploblastic
      • Paired gill pouches
      • Coelomate

      Vertebrates are grouped into five classes:

      1. Pisces
        • Body is streamlined and has fins and tail for swimming.
        • Skin is covered with scales.
        • Skeleton can be made of bone or cartilage.
        • Intake’ of oxygen is by gills.
        • Cold-blooded animals.
        • The two-chambered heart is present.
        • Examples: Fishes like Rohu, Tuna, Shark
      2. Amphibia
        • They are adapted to live both on land and water.
        • Respiration is through either gills or lungs.
        • The three-chambered heart is present.
        • Examples: Frogs, Toads, Salamander
      3. Reptilia
        • These are crawling animals.
        • Skin is rough and modified to withstand extreme temperatures.
        • The heart is three chambered in most, while four-chambered in crocodiles.
        • Cold-blooded animals.
        • Examples: Lizards, Turtles, Snakes
      4. Aves
        • Body is covered with feathers and forelimbs are modified for flying.
        • Breathing through lungs.
        • Warms blooded animals.
        • The four-chambered heart is present.
        • Examples: Sparrow, Eagle, Crow, Parrot
      5. Mammalia
        • Mammary glands are present which produce milk to nurture young ones.
        • Skin is covered with hairs and has sweat glands and sebaceous glands.
        • Warm-blooded animals with four-chambered heart.
        • Most animals are viviparous (giving birth to live young ones), some are oviparous (producing eggs).
        • Examples: Man, Horse, Kangaroo, Lion

      Conventions for writing the scientific names:

      1. The name of the genus begins with a capital letter.
      2. The name of the species begins with a small letter.
      3. When printed, the scientific name is given in italics.
      4. When written by hand, the genus name and the species name have to be underlined separately.

      NCERT Notes for Class 9 Science

      • Chapter 1 Matter in Our Surroundings Class 9 Notes
      • Chapter 2 Is Matter Around Us Pure Class 9 Notes
      • Chapter 3 Atoms and Molecules Class 9 Notes
      • Chapter 4 Structure of the Atom Class 9 Notes
      • Chapter 5 The Fundamental Unit of Life Class 9 Notes
      • Chapter 6 Tissues Class 9 Notes
      • Chapter 7 Diversity in Living Organisms Class 9 Notes
      • Chapter 8 Motion Class 9 Notes
      • Chapter 9 Force and Laws of Motion Class 9 Notes
      • Chapter 10 Gravitation Class 9 Notes
      • Chapter 11 Work, Power And Energy Class 9 Notes
      • Chapter 12 Sound Class 9 Notes
      • Chapter 13 Why Do we Fall ill Class 9 Notes
      • Chapter 14 Natural Resources Class 9 Notes
      • Chapter 15 Improvement in Food Resources Class 9 Notes

      We hope the given CBSE Class 9 Science Notes Chapter 7 Diversity in Living Organisms Pdf free download will help you. If you have any query regarding NCERT Class 9 Science Notes Chapter 7 Diversity in Living Organisms, drop a comment below and we will get back to you at the earliest.


      What are Animals?

      We all agree that a cat is an animal, but what is it that makes it an animal? Why is a sponge an animal? Why are sponges and cats placed in the same kingdom? You might think that some corals look more like plants, and that sponges don't look like much of anything at least, not like anything alive.


      Figure. 2 (Click image to enlarge)

      There are some basic features that are found in all of the members of the kingdom Animalia. In general, animals are all motile, heterotrophic, and multicellular.

      Motility refers to the ability to move and/or affect motion in one's vicinity. For example, adult sponges don't move from place to place, but they can manipulate their cells to bring food to themselves. Also, while some animals are sessile as adults, all animals exhibit movement from place to place sometime in their development. For example, sponges and corals are motile as larvae (the very early stages of embryonic development) and sessile as adults. A myriad of adaptations for motility are observed in animals, and some of these will be addressed in this tutorial. The image on the right depicts the development of a sponge.


      Figure. 3(Click image to enlarge)

      Animals are ingestive heterotrophs (they ingest nutrients). Unlike plants, who store their food as starch, animals store their food as glycogen.

      Animals have muscle tissue and nervous tissue. These tissues can range from being indistinct (as observed in sponges) to being highly complex (as observed in vertebrates). The coordination between muscle tissue and nervous tissue can result in very specialized movements (e.g., food procurement, mate pursuit, predator avoidance).


      Figure. (Click image to enlarge)


      21.E: Diverstity of Animals (Exercises) - Biology

      The scope of biology is broad and therefore contains many branches and sub-disciplines. Biologists may pursue one of those sub-disciplines and work in a more focused field. For instance, molecular biology and biochemistry study biological processes at the molecular and chemical level, including interactions among molecules such as DNA, RNA, and proteins, as well as the way they are regulated. Microbiology, the study of microorganisms, is the study of the structure and function of single-celled organisms. It is quite a broad branch itself, and depending on the subject of study, there are also microbial physiologists, ecologists, and geneticists, among others.

      Forensic Science

      Figure 1. This forensic scientist works in a DNA extraction room at the U.S. Army Criminal Investigation Laboratory at Fort Gillem, GA. (credit: United States Army CID Command Public Affairs)

      Forensic science is the application of science to answer questions related to the law. Biologists as well as chemists and biochemists can be forensic scientists. Forensic scientists provide scientific evidence for use in courts, and their job involves examining trace materials associated with crimes. Interest in forensic science has increased in the last few years, possibly because of popular television shows that feature forensic scientists on the job. Also, the development of molecular techniques and the establishment of DNA databases have expanded the types of work that forensic scientists can do.

      Their job activities are primarily related to crimes against people such as murder, rape, and assault. Their work involves analyzing samples such as hair, blood, and other body fluids and also processing DNA (Figure 1) found in many different environments and materials.

      Forensic scientists also analyze other biological evidence left at crime scenes, such as insect larvae or pollen grains. Students who want to pursue careers in forensic science will most likely be required to take chemistry and biology courses as well as some intensive math courses.

      Another field of biological study, neurobiology, studies the biology of the nervous system, and although it is considered a branch of biology, it is also recognized as an interdisciplinary field of study known as neuroscience. Because of its interdisciplinary nature, this sub-discipline studies different functions of the nervous system using molecular, cellular, developmental, medical, and computational approaches.

      Figure 2. Researchers work on excavating dinosaur fossils at a site in Castellón, Spain. (credit: Mario Modesto)

      Paleontology, another branch of biology, uses fossils to study life’s history (Figure 2). Zoology and botany are the study of animals and plants, respectively. Biologists can also specialize as biotechnologists, ecologists, or physiologists, to name just a few areas. This is just a small sample of the many fields that biologists can pursue.

      Biology is the culmination of the achievements of the natural sciences from their inception to today. Excitingly, it is the cradle of emerging sciences, such as the biology of brain activity, genetic engineering of custom organisms, and the biology of evolution that uses the laboratory tools of molecular biology to retrace the earliest stages of life on earth. A scan of news headlines—whether reporting on immunizations, a newly discovered species, sports doping, or a genetically modified food—demonstrates the way biology is active in and important to our everyday world.


      NCERT Biology Class 12 Solutions:CBSE NCERT Solutions For Class 12 Biology PDF Download

      Working on CBSE Class 12 Solutions for Biology subject will help students understand the various concepts and topics better. Class 12 Biology Solutions (Class 12 Biology NCERT Solutions) provided here have been curated by experienced academic experts at Embibe. Every solution is presented in a step-by-step and simple manner that can be easily understood. Students must go through CBSE NCERT Solutions for Class 12 Biology. Here, we have listed down the direct links for CBSE Class 12 Chapter-wise Biology NCERT Solutions:

      • Chapter 1 – Reproduction in Organisms
      • Chapter 2 – Sexual Reproduction in Flowering Plants
      • Chapter 3 – Human Reproduction
      • Chapter 4 – Reproductive Health
      • Chapter 5 – Principles of Inheritance and Variation
      • Chapter 6 – Molecular Basis of Inheritance
      • Chapter 7 – Evolution
      • Chapter 8 – Human Health and Disease
      • Chapter 9 – Strategies for Enhancement in Food Production
      • Chapter 10 – Microbes in Human Welfare
      • Chapter 11 – Biotechnology: Principles and Processes
      • Chapter 12 – Biotechnology and its Applications
      • Chapter 13 – Organisms and Populations
      • Chapter 14 – Ecosystem
      • Chapter 15 – Biodiversity and Conservation
      • Chapter 16 – Environmental Issues

      CBSE NCERT Solutions For Class 12 Biology By Embibe: Advantages

      The advantages of referring to CBSE NCERT Solutions for Class 12 Biology (NCERT Solutions Class 12 Biology) from this page are listed below:

      1. All Class 12 Biology NCERT Solutions are solved in a simple language so everyone can understand them.
      2. The solutions provided here are solved by subject matter experts of Embibe.
      3. Each and every question is being solved based on the CBSE NCERT guidelines so that students can refer to these solutions for their board exam preparation.
      4. Each and every question comes with a detailed, step-by-step solution to help students to understand the concepts better.
      5. The solutions will not only help students in their board exam preparation but will also help to clear competitive exams like NEET.

      About CBSE NCERT Solutions For Class 12 Biology: Chapter Description

      Let us now look at the chapters of Class 12 Biology and what they deal with:

      Chapter 1 – Reproduction in Organisms

      Reproduction is an essential process without which species cannot exist for long. In order to produce a progeny, each organism will go under have to reproduce sexually or asexually. The first chapter in CBSE NCERT Class 12 Biology deals with this. Learners will understand the difference between asexual and sexual means of reproduction.

      Reproduction in Organisms is a vast chapter that deals with various types of reproduction. Students will be able to differentiate between sexual and asexual methods, zoospore and zygote, and more terms. The best way to score well in this chapter is by understanding each and every concept thoroughly.

      Chapter 2 – Reproduction in Flowering Plants

      We all love flowers as they are the objects of aesthetic, ornamental, social, religious, and cultural value. They also have always been used as symbols for conveying important human feelings such as love, affection, happiness, grief, mourning, etc. But did you know that flowers are the seat for sexual reproduction in plants (Angiosperms)? Or that the myriads of flowers, the scents, and the rich colors are just an aid to sexual reproduction?

      This chapter will take you through the internal parts of a flower and how each part plays a vital role in sexual reproduction. CBSE Class 12 Biology will also give you insights into the diversity of structures of the inflorescences that ensure the formation of the end products of sexual reproduction in plants such as the fruits, and seeds.

      Chapter 3 – Human Reproduction

      After the first two important chapters on reproduction, you will now be able to examine the human reproductive systems of males and females. This chapter will help you understand the changes that occur in human beings after the puberty and cease of ovum formation in women around the age of fifty years.

      Moreover, this chapter will give you a close look at the internal male and female reproductive parts along with the remarkable differences between them. Having good knowledge of this chapter will help you score well in the Class 12 exam. Also, the chapter is important for NEET.

      Class 12 Biology Syllabus 2021-22Class 12 Biology Book PDF Download

      Chapter 4 – Reproductive Health

      This chapter deals with the emotional and social aspects of reproduction along with healthy reproduction itself. Basically, reproductive health refers to the total well-being in all aspects of reproduction such as physical, emotional, behavioral, and social.

      Through this chapter, you will learn that India was amongst the first countries in the world to initiate action programs at a national level to attain total reproductive health as a social goal. Counseling and creating awareness regarding adolescence and associated changes, safe and hygienic sexual practices, sexually transmitted diseases, etc., are a few of the practices in reproductive health.

      Through the NCERT Solutions for Class 12 Biology Chapter Reproductive Health, you will get a deeper understanding of the general aspects of reproduction.

      Chapter 5 – Principles of Inheritance and Variation

      This chapter will give you a deeper knowledge of the term “Gene” and answer several related questions of a branch of biology known as Genetics. This chapter deals with mainly the process of inheritance and the role of genes in differentiating the offspring of particular species.

      Also, you will also learn the definitions for the two most important terms in this chapter i.e., inheritance as the basis of heredity and variation as the degree by which progeny differs from their parents. You will also come across a few crucial laws of inheritance such as the Law of Dominance, Mendel’s Law, etc. This is one of the interesting chapters in Class 12 Biology.

      Chapter 6 – Molecular Basis of Inheritance

      This chapter will introduce to Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA), the two types of nucleic acids found in living systems.

      In Class 11, you must have learned the structures of nucleotides. DNA is a long polymer of deoxyribonucleotides. The length of DNA is usually defined as the number of nucleotides present in it.

      This chapter will help you identify the differences between RNA and DNA along with its detailed structure. For a better understanding of the concepts related to DNA and RNA, ensure your basics from Class 9 are strong so that you go with the flow of this Molecular Basis of Inheritance chapter.

      Chapter 7 – Evolution

      This can be one of the most interesting chapters of Class 12 Biology if you want to find the answers to the origin of life. The origin of life is considered a unique event in the history of the universe.

      In fact, the universe is very old – almost 20 billion years old. And about 2000 million years ago, the first cellular forms of life appeared on earth. There a lot of interesting theories and mythologies on how life originated on earth. Check them out and find answers using our NCERT Solutions for Class 12 Biology.

      Chapter 8 – Human Health and Disease

      Did you know that health does not constitute just the state of the body but the mind too? Health, in general, is a state of complete physical, mental and social well-being.

      This chapter will shed light on areas of genetic disorders, infections, the lifestyle of human beings, etc. Every day we are exposed to a large number of infectious agents.

      However, only a few of these exposures result in disease due to the lack of immunity. Here, you will learn the concepts of immunity, allergies in detail. You will also learn some cool public health measures that can safeguard you against infectious diseases.

      Chapter 9 – Strategies for Enhancement in Food Production

      With an ever-increasing population, the enhancement of food production is a major necessity. This chapter deals with the concepts related to food production organically. You will also come across sub-chapters such as animal husbandry, plant breeding, single-celled proteins, and tissue culture. Under animal husbandry, you will learn about fisheries, beekeeping, etc. You will also learn about apiculture and its importance in food production.

      Chapter 10 – Microbes in Human Welfare

      Microbes are organisms like bacteria and fungi that can be grown on nutritive media to form colonies and cannot be seen with the naked eyes. In this chapter, you will come across some amazing facts, such as how microbes help in curd production from milk. Even many of the beverages are produced by a process called fermentation. While discussing the good side of microbe utilization, this chapter will also take you through how it contributes to pollution.

      Chapter 11 – Biotechnology: Principles and Processes

      In this chapter, learners will get to know how Biotechnology deals with the large scale production and marketing of products and processes using live organisms, cells, or enzymes. Also, students will know about the recombinant proteins that are used in medical practice.

      Chapter 12 – Biotechnology and its Applications

      This chapter will teach students about how Biotechnology has given various useful products by using plant, microbes, animals, and their metabolic machinery.

      Biotechnology has also given rise to Genetically Modified Organisms that have been created by using methods other than natural methods so as to transfer one or more genes from one organism to another, using techniques such as recombinant DNA technology. Students will also get to know that transgenic animals are also used to understand how genes contribute to the development of a disease.

      Chapter 13 – Organism and Population

      Ecology is the study of the interactions between the organism and its abiotic environment. It mainly deals with four levels of the biological organization namely, Organism, Populations, Communities, and Biomes. The environment in which we all are living is composed of both abiotic and biotic components.

      Water, light, temperature, and soil, are the key components of the environment. Biotic components comprise all the living organisms within an ecosystem which includes plants, animals, birds, insects, bacteria, fungi, and more. Abiotic components comprise all the non-living things in an ecosystem and it includes sunlight, temperature atmospheric gases, water, and soil.

      Chapter 14 – Ecosystem

      The ecosystem is a biological community of all living things which includes plants, animals, birds, and other living organisms interacting with each other and with their nonliving components in a particular region. The non-living components include atmosphere, earth, climate, sun, soil, and the weather. Overall, the ecosystem is the network of interactions between and among organisms, and their environment. Ecosystems consist of creatures that mutually benefit from each other. Students will learn about the Ecosystem in detail in Chapter 14.

      Chapter 15 – Biodiversity and Its Conservation

      When a single species shows high diversity at the genetic level, it is called genetic diversity. When diversity is at the species level, it is called species diversity. Ecosystem-level diversity is called ecological diversity. Global diversity is divided into plants, vertebrates, and invertebrates.

      In this chapter, students will learn about what is Biodiversity, patterns of biodiversity, causes of loss of biodiversity, biodiversity conservation.

      Chapter 16 – Environmental Issues

      Major issues relating to environmental pollution and depletion of valuable natural resources vary in dimension from local, regional to global levels. Air pollution is caused by the burning of fossil fuel, e.g., coal and petroleum, in industries and in automobiles. They are harmful to humans, animals, and plants, and therefore, must be removed to keep our air clean.

      There are two major types of environmental issues – the increasing greenhouse effect which is warming the earth and the depletion of ozone in the stratosphere.

      In this chapter, students will learn about air pollution and its control, water pollution and its control, solid wastes, agrochemicals, and their effects, radioactive wastes, greenhouse effect and global warming, ozone depletion in the stratosphere, degradation by improper resource utilisation and maintenance, deforestation.

      NCERT Solutions For Class 12 Biology Free PDF Download

      We have also provided the CBSE Class 12 NCERT Solutions for Biology PDF which can be downloaded for free. Practicing Class 12 Biology Solutions will help students preparing for exams like NEET, Maharashtra CETM, etc. as well. You can also click on the links provided below and download the NCERT solution PDF directly:

      • Chapter 1 – Reproduction in Organisms
      • Chapter 2 – Sexual Reproduction in Flowering Plants
      • Chapter 3 – Human Reproduction
      • Chapter 4 – Reproductive Health
      • Chapter 5 – Principles of Inheritance and Variation
      • Chapter 6 – Molecular Basis of Inheritance
      • Chapter 7 – Evolution
      • Chapter 8 – Human Health and Disease
      • Chapter 9 – Strategies for Enhancement in Food Production
      • Chapter 10 – Microbes in Human Welfare
      • Chapter 11 – Biotechnology: Principles and Processes
      • Chapter 12 – Biotechnology and its Applications
      • Chapter 13 – Organisms and Populations
      • Chapter 14 – Ecosystem
      • Chapter 15 – Biodiversity and Conservation
      • Chapter 16 – Environmental Issues

      These resources will be extremely useful in your CBSE Class 12 preparation as well as for your NEET preparation. Make the best use of these resources and secure a very high score in your Class 12 board exams and other exams.

      FAQs Regarding CBSE NCERT Solutions For Class 12 Biology

      Here are some of the frequently asked questions and their answers:

      Q. Where can I get all the solutions for Biology Class 12 NCERT intext questions?
      A. At Embibe, we have provided solutions to all the questions for Class 12 Biology. Students can easily refer to these solutions to score good marks in their board exams.

      Q. Is the NCERT sufficient for Biology in the NEET Exam?
      A. Students who rely on NCERT Solutions for their NEET Preparation can score at least 75%+ in their NEET exams.

      Q. Where can I get Class 12 Biology NCERT exercise answers?
      A. Click Here to get Class 12 Biotechnology NCERT Exercise questions and answers.

      Q. Where can I get Class 12 Biology NCERT Chapter 2 Solutions?
      A. Click Here to get CBSE NCERT Solutions for Class 12 Biology Chapter 2.

      Q. For how many chapters NCERT Biology Class 12 Solutions available?
      A. For all 16 chapters, NCERT Solutions for Class 12 Biology is available for free on Embibe.

      Check out CBSE Class 12 solutions for other subjects from here:

      Maths NCERT SolutionsCBSE Class 12 Physics SolutionsCBSE Class 12 Mathematics SolutionsCBSE Class 12 Chemistry Solutions

      At Embibe, you can also solve CBSE Class 12 Biology Questions and take CBSE Class 12 Biology Mock Tests for free. Make the best use of these resources and take your preparation to the next level.

      We hope this article has been helpful to you. If you have any queries/doubts, leave them in the comment section below and we will get back to you at the earliest.


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      Effect Of Climate Change On Animal Diversity

      Two species of giraffe, several rhinos and five elephant relatives, along with multitudes of rodents, bush pigs, horses, antelope and apes, once inhabited what is now northern Pakistan.

      But when climate shifted dramatically there some 8 million years ago, precipitating a major change in vegetation, most species became locally extinct rather than adapting to the new ecosystem, according to an extensive, long-term study of mammal fossils spanning a 5-million-year period.

      Results of the study, by University of Michigan paleoecologist Catherine Badgley and coworkers, are scheduled to be published online in the Proceedings of the National Academy of Sciences the week of Aug. 18.

      The work has value not only in reconstructing Earth's past, but also for understanding what may lie ahead if current climate trends continue, Badgley said. "Climate is going to produce changes in ecological structure of all sorts of plants and animals around the world, now as in the past. The fossil record can help us understand how much---or how little---climate change is necessary to produce changes in ecosystems."

      Badgley is part of an interdisciplinary team of geologists and paleontologists that has been studying the fossil-rich Siwalik sedimentary rocks in northern Pakistan for more than 30 years. The Siwalik Group of sediments contains one of the world's most complete and best-studied fossil records of mammals, chronicling in a two-mile-thick deposit of rock the mammals that roamed the area from 18 to 1 million years ago. About 8 million years ago, the local climate became drier, and the prevailing vegetation changed from tropical forests and woodland to a savannah similar to that found in parts of Africa today.

      What happened next can be reconstructed from the chemistry and wear of the teeth of the plant-eating mammals, as well as the longevity of each species during the period when vegetation was changing. The teeth provide evidence of the animals' diets, revealing whether they switched to eating the newly abundant grasses when their favored fruits and broad-leafed plants were no longer available.

      Mammals that relied on fruit and browse disappeared early in the transition from forest to savannah vegetation and were not replaced, while those that ate broad leaves and grasses either adapted and persisted by changing their diets to include more grass or disappeared and were replaced by immigrant species with similar diets. By the time that savannah was the dominant vegetation, most herbivorous mammals in the area subsisted mainly on grass. The overall effect was a significant decline in the diversity of mammals in the area.

      "We see quite a different ecological profile of the kinds of mammals that coexisted after this climate change than before," said Badgley, who is an assistant professor of ecology and evolutionary biology, as well as a research scientist in the Department of Geological Sciences and the Museum of Paleontology. "It's clear that climate has had an impact on the ecological diversity of mammals in the area."

      In addition to providing compelling evidence for the effects of climate change on ecological systems, the paper is a testament to the value of long-term research in a single field area, Badgley said. "This is the kind of study you can only do after you've been working in a place with a big team for 25 years or more, because you need all the other basic data to be thoroughly resolved before you can even start to address the kinds of questions in this work. We've been fortunate to have a team that found the various research topics so worthwhile and so interesting that they stuck with it for several decades, and we've also been fortunate to receive funding for field work for that long."

      Badgley's co-authors on the PNAS paper are John Barry, Michèle Morgan and David Pilbeam of Harvard University Sherry Nelson of the University of New Mexico Kay Behrensmeyer of the National Museum of Natural History and Thure Cerling of the University of Utah. The research described in the paper was supported by a grant from the National Science Foundation.

      Story Source:

      Materials provided by University of Michigan. Note: Content may be edited for style and length.


      One of the central goals of neuroscience is to understand how the human brain gives rise to the complex behaviors, thoughts, and emotions that humans experience at every instant. Achieving such an understanding has been monumentally difficult, in part due to the complexity of the human brain. The human brain contains about 100 billion neurons and trillions of connections between them. Furthermore, neurons are not all functionally or physiologically identical – for example, within the primate retina alone there exist over 60 distinct types of neurons. While we do not have similar understanding of the diversity of neurons in the rest of the brain, some estimate that the number of different neuron types may number from 100 to 1000.

      To study a system as complicated as the brain, it is essential that we find a way to specifically manipulate and measure the system’s inputs and outputs. For example, we might want to kill or silence a certain population of neurons to assay their importance in decision-making, or we might want to record the activity in these same neurons while an individual makes decisions. For obvious ethical reasons, these manipulations cannot be done in humans, so instead many researchers study the brains and behaviors of animals such as mice and fruit flies. Research using these so-called model organisms has yielded a wealth of mechanistic insight into brain function.

      Animal models in modern neuroscience

      Work in rodents dominates modern neuroscience research. Data from the early 2000s suggest that nearly half of all neuroscientific studies were conducted in rodents1. In contrast, neuroscience research in all other mammals together accounted for less than ten percent of publications, as did research in all invertebrate species. The statistics of NIH funded grants are similar, and no data suggest that things have changed today, almost 20 years later. Beyond rodents, neuroscientists study a few other canonical model organisms – the fruit fly D. melanogaster, the zebrafish D. rerio, and the roundworm C. elegans.

      There are two main reasons why a few model organisms dominate neuroscience research. First, these are organisms for which many experimental tools are readily available. For example, mice and fruit flies have been workhorses in genetics for a century, and multiple techniques have been developed to add or remove genes in these animals. The same cannot be said for non-traditional animals that few study. The second reason is specific to rodent and primate models – as these are mammalian models, their nervous systems are more similar to that of humans, so observations made in these models more directly translate to humans.

      Given the significant advantages of using traditional model organisms, it’s fair to ask: is studying the brains of other animals worth the investment? Scientific funding is limited, so why should we allocate funds to research on non-traditional model organisms when so much can be done in traditional models? I argue that research using non-traditional model organisms has led to many fundamental discoveries about the brain and remain valuable even in modern neuroscience.

      Fundamental neuroscientific discoveries made in non-traditional model organisms

      An examination of the Nobel prizes awarded in neuroscience highlights the key role non-traditional model organisms have played in neuroscience research. The discoveries of how neurons fire action potentials, how neurons communicate with each other at synapses, and how some neurons encode information about the environment have all won Nobel prizes. One feature that all of these discoveries (and many other Nobel-prize winners) share is that they all were made in organisms that today would be considered nontraditional. The figure below comparing the distribution of modern model organisms to that of Nobel prize-winning discoveries reveals the relatively poor diversity of modern animal models.


      General Unit Information

      We share the planet with over 1 million described species of animals with many, many more awaiting discovery. The vast panorama of animal life, how animals function, live, reproduce, and interact with their environment, is exciting, fascinating, and awe inspiring. Members of the animal kingdom are among the most conspicuous living things in the world and as members of this kingdom, we have a special interest in its other members, especially those that are closely related to us. Zoology is the scientific study of animal life and builds on centuries of human inquiry into the animal world, its origins and relationships.

      Animals are highly diverse. Why are there so many more species of animals than plants? It is this diversity that forms the subject matter of this subject.

      We begin by asking the questions, What is an animal? and, How did they originate? We then start a journey of discovery by exploring the diversity of animal life and organising it in a systematic way using their evolutionary history and by examining and relating their structure with function

      By the end of this journey you will be familiar with the major groups of animals, their similarities and differences, and the evolutionary pathways that resulted in the current numbers and variety of animal species. A real appreciation of animal diversity can only be achieved through first-hand experience in the laboratory. During your practical classes you will examine all the major groups of animals, starting with the most structurally simple and finishing with birds and mammals, many of which are seen live, swimming and feeding in the temperate marine touch-tank.


      Watch the video: 6 - Grd 11 Biodiversity Of Animals Lesson Intro, Symmetry, Cephalisation (May 2022).